/*
 * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package javax.security.auth.callback;

/**
 * <p> Underlying security services instantiate and pass a
 * {@code PasswordCallback} to the {@code handle}
 * method of a {@code CallbackHandler} to retrieve password information.
 *
 * @see javax.security.auth.callback.CallbackHandler
 */
public class PasswordCallback implements Callback, java.io.Serializable {

  private static final long serialVersionUID = 2267422647454909926L;

  /**
   * @serial
   * @since 1.4
   */
  private String prompt;
  /**
   * @serial
   * @since 1.4
   */
  private boolean echoOn;
  /**
   * @serial
   * @since 1.4
   */
  private char[] inputPassword;

  /**
   * Construct a {@code PasswordCallback} with a prompt
   * and a boolean specifying whether the password should be displayed
   * as it is being typed.
   *
   * <p>
   *
   * @param prompt the prompt used to request the password. <p>
   * @param echoOn true if the password should be displayed as it is being typed.
   * @throws IllegalArgumentException if {@code prompt} is null or if {@code prompt} has a length of
   * 0.
   */
  public PasswordCallback(String prompt, boolean echoOn) {
    if (prompt == null || prompt.length() == 0) {
      throw new IllegalArgumentException();
    }

    this.prompt = prompt;
    this.echoOn = echoOn;
  }

  /**
   * Get the prompt.
   *
   * <p>
   *
   * @return the prompt.
   */
  public String getPrompt() {
    return prompt;
  }

  /**
   * Return whether the password
   * should be displayed as it is being typed.
   *
   * <p>
   *
   * @return the whether the password should be displayed as it is being typed.
   */
  public boolean isEchoOn() {
    return echoOn;
  }

  /**
   * Set the retrieved password.
   *
   * <p> This method makes a copy of the input <i>password</i>
   * before storing it.
   *
   * <p>
   *
   * @param password the retrieved password, which may be null.
   * @see #getPassword
   */
  public void setPassword(char[] password) {
    this.inputPassword = (password == null ? null : password.clone());
  }

  /**
   * Get the retrieved password.
   *
   * <p> This method returns a copy of the retrieved password.
   *
   * <p>
   *
   * @return the retrieved password, which may be null.
   * @see #setPassword
   */
  public char[] getPassword() {
    return (inputPassword == null ? null : inputPassword.clone());
  }

  /**
   * Clear the retrieved password.
   */
  public void clearPassword() {
    if (inputPassword != null) {
      for (int i = 0; i < inputPassword.length; i++) {
        inputPassword[i] = ' ';
      }
    }
  }
}
